Surface drive kit for marine craft

ABSTRACT

A marine outdrive attachable to the transom of a small fishing boat having an inboard engine. The marine outdrive includes a kit having through transom mounting plate, a fabricated propeller shaft housing pivotally attached to a pivot member which is pivotally attached to said transom plate thereby providing freedom of movement in two planes. The outdrive is supported and maintained under tension in the horizontal plane by a flexible member and a shock absorber thus maintaining automatically contact with any surface in contact with the boat&#39;s keel. A kit is provided containing all essential components and instructions for installation of the outdrive on a small fishing craft. All working components are off the shelf stock items or fabricated for easy field repair.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to outdrives for small marine craft,and more particularly to a kit for adapting a surface type drive tosmall, hallow draft fishing craft for operation in very shallow water.

2. General Background

Small marine craft are generally powered by outboard motors generallycomprising a portable, unitary structure including a power headincorporating an internal combustion engine. Such engines have a driveshaft extending vertically from the power head to a lower unittransmission gear for coupling to a horizontal propeller shaft. Theunitary unit is suspended from the boat's transom in such a manner thatthe propeller is totally submerged below the boat's keel.

Somewhat larger marine craft having deeper drafts have the option ofinboard propulsion drives which utilize submerged or surface breakingpropellers. Their deeper draft allows for mounting the engine'stransmission either inboard or outboard. In either case, the transommust be greater than that usually associated with small, shallow draftboats. Most such drives are efficient, high performance systems used forheavy loads and/or high speed.

There is, however, a need for a propulsion unit which will allow small,shallow draft boats to travel at low speed in very shallow water. Sincemost outdrive systems are expensive and complicated, as is illustratedby U.S. Pat. Nos. 4,976,638, 4,775,342, 5,279,509, 3,933,116, and5,326,294, and require expert installation, there is a need for anuncomplicated, easily installable inboard-outdrive for small craft suchas small flat bottom fishing boats. Through transom direct drives suchas that disclosed by U.S. Pat. Nos. 4,976,638, 4,544,362, and 4,645,463provide a more simplified drive in the form of a pivotal ball joint,these drives are still expensive due to their special pivotal joints andcast housing. Therefore, there is still a need for a simple, inexpensiveoutdrive which can be installed by the average person on most smallfishing boats.

SUMMARY OF THE INVENTION

The present invention puts the inboard outdrive technology withineconomic reach of the small boat fisherman, thereby allowing thefisherman to gain access to fishing spots otherwise not accessible dueto shallow water. By providing an inexpensive, simple kit with easy tofollow instructions, the small boat owner can adapt an inboard outdrivekit to his boat in a manner of hours. It is therefore an object of theinvention to provide an inboard outdrive kit which includes a templatefor locating the holes cut and drilled in the boat's transom, allhardware necessary to complete the outdrive assembly, a line-up shaftfor connection to a range of engine sizes, a lifting device for liftingthe outdrive clear of the water. Engines and couplings are sized andrecommended for a number of engine sizes but not furnished as part ofthe kit. The drive provides connections for attaching a hydraulicsteering system which may be purchased in kit form as well.

It is another object of the present invention to provide an inexpensive,marine outdrive apparatus having a thrust angle which is nearlyhorizontal particularly adapted to provide a surface-piercing propeller,although not necessarily limited to such use.

It is yet another object of the invention to provide an outdrive whichis simple and easily maintained with off the shelf parts.

Still another object is to provide an outdrive which may be adapted tomost small fishing boats and controlled by a variety of steering orelevating apparatus.

Another object of the invention is to limit the downward angle of thedrive to an approximate horizontal plane and maintain a self-adjustingdownward force on the outdrive unit, thereby allowing the drive toabsorb any shock produced by obstructions under the boat.

Still another object of the invention is to allow the propeller toengage mud and continue to propel the boat in the near absence of waterunder the boat's keel.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and objects of the presentinvention, reference should be made to the following detaileddescription taken in conjunction with the accompanying drawings, inwhich, like parts are given like reference numerals, and wherein:

FIG. 1 is an isometric view of the outdrive kit as assembled;

FIG. 2 is an isometric view of the transom template;

FIG. 3 is a partial isometric view of the rear portion of a small boatwith template shown in FIG. 2 attached;

FIG. 4 is a partial isometric view of the assembled outdrive attached toa boat transom; and

FIG. 5 is an exploded view of the outdrive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As illustrated in FIG. 1, the outdrive assembly 10 includes a transomattachment 12 consisting of a frame portion 14 which bolts to the faceof a boat transom 18 shown in FIG. 3 and a recessed portion 16 whichextends through the transom 18; a pivot member 20, best seen in FIG. 5,is pivotally about its vertical axis, and is attached via upper andlower flange bearings 22, screws 23 and nuts 19 to the transomattachment 12; a stub shaft 24 inserted through a flange bearing 26,attached to the transom attachment 12 via screws 27, the stub shaft 24extending through the recessed portion of the transom attachment 12, andconnected at one end to a universal joint 28 via screws 25 which in turnis connected to the propeller shaft 30 via screws 29 the stub shaft 24is also connected to a coupling 21 at its opposite end; and a shafthousing assembly 32 including a tube portion 34 having an internalbushing 36 and a flange bearing 38 for supporting the propeller shaft30. The shaft housing assembly further comprises a horizontal clevisportion 40 having ears 42 and webs 41 attached horizontally to one endof the tube portion 34 in a manner whereby the shaft housing 32 ismountable in a horizontal plane to the pivot member 20 via flangebearing 44, screws 23 and nuts 19; a lower stabilizing fin 46 attachedvertically to the tube portion 34; a dorsal fin 46 attached verticallyto the tube portion 34 at approximately a 30 degree angle; a horizontalanti-cavitation plate 50 attached to the dorsal fin 48; and a propeller52 attached to propeller shaft 30 and threadably secured with a nut 54.The propeller 52 is a weedless two blade type propeller. This allows thelead or pitch of the propeller 52 to serve as a screw when engaging mud,thereby propelling the boat even when there is little or no waterpresent under the keel of the boat. The lower fin 46 slices into themud, thereby allowing the propeller to engage the mud. Theand-cavitation plate 50 further includes a rib or cleat member 54 havinga hole 56 for attaching a safety chain 57 for supporting the outdrive 10in a horizontal position and a second hole 56 for attachment of a cable59 used to lift the drive units clear of the water via a pullychainbracket 61 and its accompanying winch assembly, not shown but includedas part of the kit. Bracket ears 58 are also provided attached to thetube portion 34 for connection via a pin 60 to the rod end of a shockabsorber 64, the butt end connection 65 being a swivel joint, mountableto the boat transom 18 as seen in FIG. 4. The shock absorber 64 is intension, thereby keeping the chain 57 taut when the drive 10 ishorizontal. Therefore, if an obstruction is encountered by the lower fin46, the drive 10 displaces the shock absorber 64 then returns to itsoperating position without bouncing or allowing the drive to exceed apreset angle. A template 68 is provided as seen in FIG. 2 and shown inplace in FIG. 3 on a small fishing boat for marking the mounting holes70 and cutout 72 for receiving the recessed portion 16 of transomattachment 12. FIG. 4 illustrates how the assembled unit 10 is installedon a small fishing boat.

By having the pivot member 20 pivotal about its vertical axis whenmounted to the transom attachment 12 via bearing 22 and the horizontalclevis portion 40 of the housing assembly 32 attached to the pivotalmember 20 at 90 degree angles, the housing assembly 32 has freedom ofmovement in both horizontal and vertical planes. The universal joint 28is positioned so that its center lines correspond with that of the pivotmember 20 bearing 22 axis. All bearings 22, 26, 38, 44, the universaljoint 28, the propeller 52, shaft coupling 21, as well as the shockabsorber 64, are commercial items readily available off the shelf inmost hardware, automotive or marine supply stores. However, theuniversal joint 28 may be modified by grinding a portion of the joint ina manner whereby a greater degree of angulation is achieved. The shafthousing assembly 32 is a fabricated assembly rather than a single castcomponent to allow for easy field repair. A variety of engines may beused, depending on the capacity of the craft.

It should also be noted that a pivot pin 15, seen in FIG. 1, is attachedto the upper side of the tube portion 34 to provide a connecting pointfor a steering actuator 78 as illustrated in FIG. 4 provided as anoptional accessory to the outdrive kit.

Because many varying and different embodiments may be made within thescope of the inventive concept herein taught, and because manymodifications may be made in the embodiments herein detailed inaccordance with the descriptive requirement of the law, it is to beunderstood that the details herein are to be interpreted as illustrativeand not in any limiting sense.

What is claimed is:
 1. An outdrive kit for attachment to a small fishingcraft comprising:a) a transom attachment having vertical pivot mounts;b) a pivot member pivotally attachable to said transom attachment,having horizontal and vertical pivot mounts; c) a first propeller shaftmember rotatably mountable to said transom attachment; d) a propellershaft housing having a second propeller shaft rotatable therein and apivotal clevis attachment mountable to said pivot member horizontalmounts; e) a plurality of bearings for mounting said pivot member, saidpropeller shaft housing and said first propeller shaft member; f) auniversal joint attachable to said first propeller shaft and said secondpropeller shaft; g) a propeller attachable to said second propellershaft; h) a chain for supporting said propeller shaft housing in ahorizontal plane; i) a cable and winch for lifting said propellerhousing relative to said small fishing craft; j) a shock absorberattachable to said propeller shaft housing; k) a packet of assortedfasteners for connecting elements a-j; l) a template for locatingmounting holes for said transom attachment; and m) instructions andillustrations detailing how to mount said kit to a small fishing craft.2. An outdrive kit for attachment to a small fishing craft according toclaim 1, further including a steering kit comprising a means forpositioning said propeller shaft housing horizontally relative to saidcraft.
 3. A method for attaching an outdrive to a small fishing craftcomprising the steps of;a) providing an outdrive kit comprising:i) atransom attachment having vertical pivot mounts; ii) a pivot memberpivotally attachable to said transom attachment, having horizontal andvertical pivot mounts; iii) a first propeller shaft member rotatablemountable to said transom attachment; iv) a propeller shaft housinghaving a second propeller shaft rotatable therein and a pivotal clevisattachment mountable to said pivot member horizontal mounts; v) aplurality of bearings for mounting said pivot member, said propellershaft housing and said first propeller shaft member; vi) a universaljoint attachable to said first propeller shaft and said second propellershaft; vii) a propeller attachable to said second propeller shaft; viii)a chain for supporting said propeller shaft housing in a horizontalplane; ix) a cable and winch for lifting said propeller housing relativeto said small fishing craft; x) a shock absorber attachable to saidpropeller shaft housing; xi) a packet of assorted fasteners forconnecting elements a-j; xii) a template for locating mounting holes forsaid transom attachment; and xiii) instructions and illustrationsdetailing how to mount said kit to a small fishing craft; b) locatingand cutting mounting holes in the transom of a small fishing craft persaid template; c) assembling said outdrive per said instructions andillustrations; d) mounting said outdrive to said transom; e) securingsaid chain to said propeller housing and said transom in a mannerwhereby said outdrive is held in a horizontal plane; f) attaching saidshock absorber to said transom in a manner whereby a tension is exertedon said propeller housing; g) attaching said cable and winch assembly tosaid transom and attaching its cable to said propeller housing; h)attaching a coupling to a portion of said first propeller shaft; i)attaching said coupling to an engine; and j) providing a means forpivoting said propeller housing in a horizontal plane.
 4. The methodaccording to claim 3 further comprising the step of grinding away aportion of said universal joint to allow for a greater degree ofangulation.
 5. A method of maintaining propulsion of a small marinecraft in the near absence of water comprising an outdrive kit having apivotal propeller shaft and housing including a propeller said kitmounted on the transom of a small craft, the shaft held in essentially ahorizontal plane by a flexible lifting means and in downward tension bya shock absorber with sufficient force to insure propeller contact witha mud surface, said propeller shaft having a trust angle which is nearlyhorizontal and positioned to insure near perpendicular propeller contactwith the mud bottom when in near contact with the bottom of the craft ina manner whereby said propeller engages said mud surface in a screw likemanner thereby providing continuous propulsion through said mud.